Protective means for alternating-current systems.



B. F. W. ALEXANDERSON. PROTECTIVE MEANS FOR ALTERNATING CURRENT SYSTEMS.

APPLIGATION FILED JULY 1e, 190a.'

Lhm-

PATENTED MAY 1, 1906.

'ssorizoriva MEAN-E3 To (1.]! 112 mm him/1y oomrcrn:

it known that l, ERNST 1*. W. ALEXA DERSOX, a subject of the King of Swcilcn aml Nor 'ay, residing at; Schenectady,county of Schenectady, State of New ll ol'li, have invented certain new and use ful lmprovcmcnis in Protective Means forAltcrnatmgr-Current Sysccms, of which the following is a specificat-ion.

li hm sovsral lransinission-lincs are running between a main and a sub station, some oro'rision must be mails so'thalif a shortrncuii occurs in one line Ehat line will hc cu l only 1 she main-station coil of thc lino tho orcrloaii-rclays will talcc. care of it, but at the substation some special (lawn-o must he used-l ar instants, reverse current relays. Ii"fil=-Cl1ililil relay can ho ilcsigneil in hilcrcm Ways, lint always contains onc coil carryinga current euuivalonl to the line-cur rcnl. anil onc coil carrying a cin'rcnt cquivalonl to he polonlial of the linc. Thc rclays whirli have been used hsrctoi oro may fail to worl if the short, circuit is sn'lliricntly soverc lo causc lhcpoioritial of the lino to drop iiown lo ZtFlL in such a case tho pocmilial-coil would lose? ilsrurrcnl. "ihcprohlr-mia ihcrelorc to hold up l-hv potential some few sccomls until ii. rrlay has tripocil the switch. This may loc accomplishcil in the following Way:

From a porcnlial-lranslormer is driven a little syz *hronous motor-goncralor set, which foods rho poicntialwoil of the relay with altcrnaiing current cxactly the same Way as that coil woulilhavc lmon loll nirootly from the po'iicntiail-transformer. 'lho'motor and the gcnorator are-coupled by a clutch, which. ilrircs in one iliroclion only and pcrmils thevcnorator to run free if thc molor stops. i vhon tho lino is shorl-circuilcil and the potential drops (i(l3'i'll,lill0 motor will usr its niomonium to l'ccil cnrrmit into thc shorl circuit and will slop vcry quickly; lHl$ lhc generator will have cnough lly iccl cilcct to ooniirino its synchronous moi'ion for sonic seconds and will hold up thc polcnlial on ihc relay-until it has irip )Lil. Uuc motor-gunerallor set of course will sr-rvcfor all lhcrclays of tho station.

My invontion thcrclorc oompriscs, hroailly, a system in which a ccssation oi potcntial on an altornating-ourrcnt lino scis l'rco storml energy to excite tho potontial-ooil .of aurorr. arazxafinsssos, O1 -S(Jl-lENEC"ADY., NEW was, Ass

11a oo irona'r oa or NEW YUR YEQNATEhlQ-Z GURFhEHT srsrsrasi Speoification of Letters Patent." Applicatien filed July 16, 1903.

sary, as the fund sos Pstezited'may 1, 1906., Serial r5. lhoflfila verse-current relay.-

prefer to store the energy given-ugly thc'ali'crnatinq current itscll hull this would not in all cascs oe' necesainntal ifeaturo of the invention is to provide fora tmporary excitation of the otential-coilqv The several novel features w'i l be hsrcinaftr'more fully indicated.

In the accompanying drawing is shown (liagraimnaric'ally a' system embodying my. improvements.

1 Z 3 rcpresentbus-bars, which may he in a substation or lll; other points whci'ic protection against rcvcrsal oi cnorgy-iloav is requircil.

4 represents an automatic switch ,controlled by a -.trip-coil 5, cn'crgizcd by a local soul-cc, as 6, thc circuit of which is controlled by rclays To. These rclays should he sufiicicnl: in numhcr lo rcspoml to a rcvcrsal on any phasc of thc sysrcm. Although a triphasc systom shown, the invention is applicable to any type of alternating rnrrcrit systcizi. The relays, as usual, arc pro iilcil Wll h cur'rcnt and pot'cntial coils, as 9 '10 '9 10; The potentialwoils instead of lic ingjiiariycd from a po- Milllll llllHSfQl'lllQl clircctly,"which is the ordinary practicc; arc (Kclffll by a generator 11. driven by a synchronous motor 12, oper alcd zhrongh a transi'ormcr (l3; i

H is a ilircctcurrc1it oxci'tcr for the motor and gcnorator. Bcnvccn thc motor anilgcncrator is a clutch 15, adapted to (lisconncct themwhenlinc-polcntialfails. l 'oroxamplc, two ratchct-liu-cil memhcrs may be hclaltogcthor so long as tho motor is driving: but \vhcn it lags or stops thc gcncrator, umlor ii's momcntum, may run alwail. Thus the oocrgy stored in thc Form of momcnium by the ordinary opcration will maintain potential on tho coils ll) 10" ol the rclays and in casc of a rcvcrsal olcurrcni in thc scrics coils l'cil hy transhn'mcrs w ill the trip-coil of lhc switch or (ilt'liil-l ii"2lli1 will surcly he opcratcil a-nil lhc allcrnating-currcnt circuii hrolicn Many olhcr ways may hc omploycil for maintaining thc chargc ol thc potmitial rclay-coils, which will occur to l skilled cnginccr.

' What l claim iii'snvw, and ilcsilrc to sccuro by Lctlcrs lalcnt ol thc l nilcil Stairs, is-

1. An altcrnaring-currcnt system comprisooiriprising a. current-coil, a. potential-coil, and

moons for girolonging the action of the potential-ooil v: ion potential on the line ceases.

o. The combination with on alternzitixig current system, oi EL switch or GlICUlt-bifltt-lifii,

a. reverso-ourrent relay for trip ping the some having moment-coil and. a potontittl-coil,m1ti means for prolonging the iusgnstizstion of the potential-coil under cessation of potential in the system.

. t. The combination with an alternatingoiu'reno system, of a switch or circuit-breaker, a, reverse-current 30121 for tripping the sumo havinflzi current-coil Hi l a potential-coil su lied y the system, and means between t e fines and the potential-coil for delaying its domagi'iotizstion under short circuit iii the system.

5. The combination Wibli an alternatingcurront system, of o reverse-current relay oontrolling the stuns, said. relay having it o 11- ront--coil and potential-coil, and a synchrol l i l l l l l l l l l nously-op'eriitml source of supply for the po tentiiil-coil.

The combination with an alternating-- current system, of it rovorso-rurrmit relay controlling the some, said relay having a current-coil and it potential-coil, and it synchronous generator for energizing the potentialcoil.

7. The combination with an alternating curront system, of it rovorsc-ourrout relay controlling the some, said relay lowing a. ourrent-ooil and a potontialwoil, and at yn :hronous i11o'tor-gonorator (or vnt-rgizaing tlio potontinlroil.

5. The combination with no ziltornutiii current system, of a rev( rso-corrent rat-lay controliing the some, said re ay having it our- EFLJZbtJOll and :1 potential-coil, ii synchronous motor, agonorator operated thereby for onorgizing theoLontiulwoil, tlIlll a slip Connortion between tho motor antl gonorutor to p01- mit tho-latter to run when the former slows down 01 stops.

1n witness whereof l have hereunto sot my hand this 3d (lay of July, 1903.

BENJAMIN llULL, HELEN (limo-1w. 

